I have discovered something, much to my confusion and frustration.
some iframes don't seem to like to work at all in wordpress.
but some do.
youtube/vimeo embeds work fine.
most iframes seem to work fine, i've used them to embed entire pages from other sites like amazon.
but when i try to embed banners or specific product widgets from amazon, they don't work at all. I get nothing but empty space.
but when i put those same banners and widgets in a static html page for testing purposes, they work perfectly fine.
anyone have an idea why they will not work in wordpress?